[petsc-users] MatMultTranspose memory usage

[Karl Lin]

We used /proc/self/stat to track the resident set size during program run,
and we saw the resident set size jumped by the size of the matrix right
after we did matmulttranspose.

On Wed, Jul 17, 2019 at 12:04 PM hong--- via petsc-users <
petsc-users at mcs.anl.gov> wrote:

> Kun:
> How do you know 'MatMultTranpose creates an extra memory copy of matrix'?
> Hong
>
> Hi,
>>
>>
>>
>> I was using MatMultTranpose and MatMult to solver a linear system.
>>
>>
>>
>> However we found out, MatMultTranpose create an extra memory copy of
>> matrix for its operation. This extra memory copy is not stated everywhere
>> in petsc manual.
>>
>>
>>
>> This basically double my memory requirement to solve my system.
>>
>>
>>
>> I remember mkl’s routine can do inplace matrix transpose vector product,
>> without transposing the matrix itself.
>>
>>
>>
>> Is this always the case? Or there is way to make petsc to do inplace
>> matrix transpose vector product.
>>
>>
>>
>> Any help is greatly appreciated.
>>
>>
>>
>> Regards,
>>
>> Kun
>>
>>
>>
>> Schlumberger-Private
>>
>
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